Interpretive Summary: As a result of an increased occurrence of obesity and the medical problems associated with it, a movement towards decreasing obesity has resulted in an effort to develop healthier foods. Diets higher in soluble fiber, beta-glucan, are known to decrease cholesterol level and improve glucose and insulin regulation. Since 1990, three types of oat products, Oatrim, Nutrim, and C-Trim, that contains concentrated amount of beta-glucan, were developed and patented by a USDA laboratory (NCAUR) in Peoria, IL. When developing healthier foods containing soluble fiber, it is important to determine its content by an accurate method. This study was conducted to determine the amount of soluble fibers present in various developed oat products. The methods used were the Flow-injection Analysis (FIA) and an enzyme method. Both methods showed good agreements with each other and revealed differences between nominal and actual content of beta-glucan in the products. Molecular weight distribution data revealed that the rigorous processing condition, i.e., jet-cooking, of these oat products influences the molecular size of beta-glucan. This research provides industries that produce the foods containing beta-glucan with a reliable quality control method and will benefit scientists in industry and academia developing analysis method of beta-glucan.

Technical Abstract:
The soluble fiber, beta-glucan, in the oat products is known to be an active hypolipidemic component that is responsible for lowering plasma lipids. Quantitative analysis of beta-glucan in oat hydrocolloids such as Oatrim, Nutrim, and C-Trim was performed to measure the total beta-glucan content and molecular weight distribution. For the measurement of total beta-glucan content, both modified flow-injection analysis (FIA) method and standard AACC enzymatic method were employed. FIA method makes use of the enhanced fluorescence produced when beta-glucan forms complexes with Calcofluor. Experimental results from both modified FIA method and standard AACC enzymatic method revealed very good coincidence with each other. This result confirms the applicability of either technique for the quantitative evaluation of beta-glucan in hydrocolloids. Molecular weight (MW) distribution of beta-glucan was determined by size-exclusion chromatography with postcolumn detection method. Experimental results revealed that the molecular weight of beta-glucan in the Trim products was decreased during the manufacturing process. This result was ascribed to the rigorous processing condition of jet-cooking.